One method employed in the past in the field of surgery for conditions such as cataracts involves extracting the intracapsular crystalline lens through a surgical incision made in ocular tissue such as the cornea (sclera) or anterior capsule section of the lens, and once the lens has been removed, inserting an intraocular lens serving as a replacement for the crystalline lens into the eye through the incision and arranging it within the capsule.
Particularly in recent years, methods that employ an intraocular lens insertion tool like those disclosed in Patent Citations 1 to 3 have come into widespread use. Where such an insertion tool is employed, the intraocular lens can be inserted into the eye without expanding the surgical incision that was made for the purpose of extracting the crystalline lens, thereby reducing the labor entailed in the surgical operation, as well as reducing the risk of post-surgical astigmatism or infection.
Most of the conventional insertion tools, including those disclosed in Patent Citations 1 to 3, are adapted to enclose the intraocular lens within the insertion tool by placing the intraocular lens in a recloseable hinged portion, and then closing the hinged portion to shut the intraocular lens inside.
However, in an insertion tool having such a construction, there is a risk that, when the hinged portion is closed to enclose the intraocular lens within the insertion tool, once the hand is released from the hinged portion the hinged portion will open inadvertently, allowing the intraocular lens to fall out. This created a need for an additional operation, performed after the hinged portion is closed, to secure the hinged portion in the closed state using a retaining member such as a sleeve.
An additional risk encountered in the process of closing the hinged portion to shut the intraocular lens inside was that the position of the intraocular lens would move slightly, so that it could not be imparted with initial deformation in the desired shape. If the intraocular lens is not correctly imparted with initial deformation, subsequent plunging out of the intraocular lens may not proceed smoothly, and in some instances the intraocular lens may be subjected to unnecessary force, with a risk of possible damage to the intraocular lens.
Patent Citation 1: Japanese Patent Publication 3412103
Patent Citation 2: Japanese Patent Publication 3420724
Patent Citation 3: Japanese Patent Publication 3665643